drm/nouveau/gr: enable memory loads on helper invocation on all channels

We have a lurking bug where Fragment Shader Helper Invocations can't load
from memory. But this is actually required in OpenGL and is causing random
hangs or failures in random shaders.

It is unknown how widespread this issue is, but shaders hitting this can
end up with infinite loops.

We enable those only on all Kepler and newer GPUs where we use our own
Firmware.

Nvidia's firmware provides a way to set a kernelspace controlled list of
mmio registers in the gr space from push buffers via MME macros.

v2: drop code for gm200 and newer.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: David Airlie <airlied@gmail.com>
Cc: nouveau@lists.freedesktop.org
Cc: stable@vger.kernel.org # 4.19+
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230622152017.2512101-1-kherbst@redhat.com